Smite promptly, and the surprise and sting of your injustice should provoke an excellent reply.  And where there is least ground for suspicion, there, remember, is the most.  The right hand of fellowship extended towards you is one of the best openings you have.  “Not such a fool,” is the kind of attitude to assume, and “You don’t put upon me so easy.”  Your adversary resents this a little, and, rankling, tries to explain.  You find a personal inference in the expostulation.

Next to a wariness respecting your interests is a keen regard for your honour.  Have concealed in the privacy of your mind a code of what is due to you.  Expand or modify it as occasion offers.  Be as it were a collector of what are called “slights,” and never let one pass you.  Watch your friend in doorways, passages; when he eats by you, when he drinks with you, when he addresses you, when he writes you letters.  It will be hard if you cannot catch him smuggling some deadly insult into your presence.  Tax him with it.  He did not think, forsooth!  Tell him no gentleman would do such a thing, thinkingly or not; that you certainly will not stand it again.  Say you will show him.  He will presently argue or contradict.  So to your climax.

Then, again, there is the personal reference.  “Meaning me, sir?” Your victim with a blithe heart babbles of this or that.  You let him meander here and there, watching him as if you were in ambush.  Presently he comes into your spring.  “Of course,” you say, “I saw what you were driving at just this minute, when you mentioned mustard in salad dressing, but if I am peppery I am not mean.  And if I have a thing to say I say it straight out.”  A good gambit this, and well into him from the start.  The particular beauty of this is that you get him apologetic at first, and can score heavily before he rises to the defensive.

Then, finally, there is your abstract cause, once very fruitful indeed, but now sadly gone in decay, except perhaps in specialist society.  As an example, let there be one who is gibing genially at some topic or other, at Japanese king-crabs, or the inductive process, or any other topic which cannot possibly affect you one atom.  Then is the time to drop all these merely selfish interests, and to champion the cause of truth.  Fall upon him in a fine glow of indignation, and bring your contradiction across his face—­whack!—­so that all the table may hear.  Tell him, with his pardon, that the king-crab is no more a crab than you are a jelly-fish, or that Mill has been superseded these ten years.  Ask:  “How can you say such things?” From thence to his general knowledge is a short flight, and so to his veracity, his reasoning powers, his mere common sense.  “Let me tell you, sir,” is the special incantation for the storm.